MXPA02004838A

MXPA02004838A - High temperature super-conducting rotor coil support with split coil housing and assembly method.

Info

Publication number: MXPA02004838A
Application number: MXPA02004838A
Authority: MX
Inventors: John Nygard Robert
Original assignee: Gen Electric
Priority date: 2001-05-15
Filing date: 2002-05-14
Publication date: 2004-12-13
Also published as: DE60238370D1; CN1385949A; PL353907A1; EP1261106A2; CZ20021670A3; KR20020087348A; ES2355061T3; US20020171318A1; US6815860B2; NO20022298L; BR0201834A; ATE489763T1; CN100338858C; EP1261106B1; CA2384582C; US20030173862A1; NO330712B1; KR100902431B1; CA2384582A1; PL203119B1

Abstract

A rotor is disclosed for a synchronous machine comprising: a rotor core; a super-conducting coil winding extending around at least a portion of the rotor, said coil winding having a side section adjacent a side of the rotor core; at least one tension rod extending through a conduit in said rotor core; and a housing attached to the tension rod and connected to the side section of the coil winding, wherein the housing comprises a pair of side panels.

Description

SUPPORT OF ROTOR COIL SUPER HIGH TEMPERATURE DRIVER WITH DIVIDED COIL HOUSING AND ASSEMBLY METHOD BACKGROUND OF THE INVENTION The present invention relates generally to a super-conductive coil in a synchronous rotating machine. More particularly, the present invention relates to a coil support structure for winding super-conductive fields in the rotor of a synchronous machine. Synchronous electric machines have field coil windings that include, but are not limited to, rotary generators, rotary motors and linear motors. These machines generally comprise a stator and a rotor that are coupled in electromagnetic form. The rotor may include a multiple pole rotor core, and one or more coil windings mounted on the rotor core. The rotor cores may include a solid, magnetically permeable material, such as an iron core rotor. Conventional copper windings are commonly used in the rotors of synchronous electric machines. However, the electrical resistance of the copper windings (although low by conventional measures) is sufficient to contribute to the substantial heating of the rotor and to decrease the power efficiency of the machine. Recently, superconducting coil windings (SC) have been developed for rotors. The SC windings effectively have no resistance and are highly advantageous rotor winding windings. The iron core rotors are saturated at an air space magnetic field strength of approximately 2 Tesla. The known superconducting rotors employ air core designs, without iron in the rotor, to achieve magnetic fields of air space of 3 Tesla or higher. These high space-air magnetic fields produce increased energy densities of the electric machine, and result in a significant reduction in weight and size of the machine. Superconducting air core rotors require large amounts of superconducting cables. Large amounts of SC wire are added to the required coil number, the complexity of the coil supports and the cost of the windings and the SC coil rotor. High temperature SC (HTS) coil field windings are formed of superconducting materials that are brittle, and must be cooled to a temperature at or below a critical temperature eg, 27 ° K, to achieve and maintain superconductivity . The SC windings can be formed of a high temperature superconducting material, such as the conductor based on BSCCO (BixSrxCaxCuxOx). The superconducting coils have been cooled by liquid helium. After passing through the rotor windings, the heated used helium is returned as gaseous helium at room temperature. The use of liquid helium for cryogenic cooling requires a continuous relicuefaction of the gaseous helium at room temperature returned and said relicuefaction poses significant reliability problems and requires significant auxiliary energy. The above SC coil cooling techniques include the cooling of an SC coil impregnated with epoxy through a conduction path from a cryocooler. Alternatively, the cooling tubes in the rotor can transfer a gaseous liquid and / or cryogen to a coil winding SC that is immersed in the flow of the liquid and / or gaseous cryogen. However, immersion cooling requires that the entire full field winding and rotor structure be at cryogenic temperature. As a result, iron can not be used in the magnetic circuit of the rotor due to the brittle nature of iron at cryogenic temperatures. What is needed is a super conductor field winding assembly for an electrical machine that does not have the disadvantages of supercooled liquid-cooled and air-core super-field winding assemblies., for example, the known super-conductor rotors. In addition, HTS coils are sensitive to degradation from high bending and tensile stresses. These coils must undergo centrifugal forces, which stress and extend the windings of the coil windings. The normal operation of electric machines involves thousands of start and stop cycles over the course of several years that result in a low cycle fatigue load of the rotor. In addition, the HTC rotor winding must be able to withstand 25% of operation at high speed during the rotor balancing procedures at room temperature and without affecting the conditions of over operating speed in cryogenic temperatures during the generation operation. of energy. These over-speed conditions substantially increase the centrifugal force load on the windings during normal operating conditions. The SC coils used as the HTS rotor field winding of an electric machine are subjected to stresses and stresses during cooling and normal operation. They are subject to centrifugal load, torque transmission and transient fault conditions. In order to withstand the forces, tensions, stresses and cyclic loads, the SC coils must be adequately supported in the rotor by means of a bobbin support system. These support systems hold the SC coils in the HTS rotor and secure the coils against the enormous centrifugal forces due to the rotation of the rotor. In addition, the coil support system protects the SC coils, and ensures that the coils do not crack, fatigue or otherwise fail prematurely. The development of protectors and bobbin support systems for the HTS coil has been a major challenge in the adaptation of the SC coils to the HTS rotors. Examples of the coil support systems for the HTS rotors that have been previously proposed are described in U.S. Patent Nos. 5,548,168; 5,532,663; 5,672,921; 5,777,420; 6,169,353, and 6,066,906. However, these coil support systems have several problems, such as they are expensive, complex and require an excessive number of components. There is also a need for a coil support system made with low cost and easy to manufacture components.

BRIEF DESCRIPTION OF THE INVENTION A coil support system has been developed for the high-temperature super-conductive coil winding (HTS) in the form of a track for a two-pole rotor of an electric machine. The coil support system prevents damage to the coil winding during rotor operation, supports the coil winding with respect to centrifugal and other forces, and provides a safety guard for the coil winding. The support system supports the coil winding with respect to the rotor. The HTS coil winding and the coil support system are at cryogenic temperature while the rotor is at room temperature.

The split housing coil support is particularly useful for a high temperature, low energy density super high voltage electrical machine (HTS). The support system withstands the high centrifugal and tangential forces that would otherwise act on the SC coil. The coil housings are positioned end to end along the large side sections of the coil winding in order to evenly distribute the centrifugal and tangential forces acting on the coil. To reduce heat release, the mass of the coil support has been reduced to a minimum in order to reduce thermal conduction from the rotor through the support inside the cold coil. The coil support is maintained at cryogenic temperature, as does the field winding. The coil support system includes a series of coil support assemblies extending between opposite sides of the track coil winding. Each coil support assembly includes a tension bar and a pair of split coil housings. The tension rods extend between opposite sides of the coil winding through conduits, eg, holes, in the rotor core. A coil housing divided at each end of the tension bar is attached to the coil. The housing transfers the centrifugal forces from the coil to the tension bar. Each coil support assembly supports the coil winding with respect to the rotor core. The series of coil support assemblies provide a solid and protective support for the coil winding. Each divided coil housing comprises a pair of opposed side panels that are assembled around the coil SC and hold one end of the tension bar. The side panels are "C" shaped pieces which are held together by bolts to enclose the coil between a pair of side panels. The retaining bolts retain the side panels together and prevent the coil housing from sliding under the high tangential and centrifugal loads. The HTS rotor can be from a synchronous machine originally designed to include SC coils. Alternatively, the HTS engine can replace a copper coil rotor in an existing electrical machine, such as a conventional generator. The rotor and its SC coils are described herein in the context of a generator, although the HTS coil rotor is also suitable for use in other synchronous machines. The coil support system is useful in the integration of the coil support system with the rotor and the coil. In addition, the coil support system facilitates easy preassembly of the coil support system, the coil and the rotor core before the final rotor assembly. The pre-assembly reduces the coil and rotor assembly time, improves the quality of the coil support and reduces the variations of coil assembly.

In a first embodiment, the invention is a rotor for a synchronous machine comprising: a rotor core; a super-conductive coil winding extending around at least a portion of the rotor core, the coil winding having a side section adjacent to a side of the rotor core; at least one tension bar that extends through a conduit in the rotor core; and a housing attached to the tension bar and connected to the side section of the coil winding, wherein the housing comprises a pair of side panels. In another embodiment, the invention is a method for supporting a super-conductive coil winding in the rotor core of a synchronous machine comprising the steps of: extending a tension bar through a conduit in the rotor core; placing the coil winding around the rotor core so that the tension bar tension bolt extends between the side sections of the coil winding; assembling a pair of side panels of at least one housing around a side section of the coil winding; securing the side panels together, and attaching the housing to the first end of the tension bar.

BRIEF DESCRIPTION OF THE DRAWINGS The following drawings in conjunction with the specification text describe one embodiment of the invention.

Figure 1 is a schematic side elevational view of a synchronous electric machine having a superconducting rotor and a stator. Figure 2 is a perspective view of an illustrative track superconducting winding winding. Figure 3 is a partially cut away view in the rotor core, the coil winding and the coil support system for a super high temperature (HTS) rotor. Figures 4 and 5 are perspective views of a split coil housing having a coil (Figure 5) and without a coil (Figure 4). Figure 6 is a perspective view of the rotor core, the coil winding and the coil support system for a super high temperature (HTS) rotor.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows an illustrative synchronous generator machine 10 having a stator 12 and a rotor 14. The rotor includes field winding coils which fit within the cylindrical cavity 16 of the stator. The rotor fits inside the cavity to the stator vacuum 16. As the rotor rotates within the stator, a magnetic field 18 (shown by dashed lines) generated by the rotor and the rotor coils moves / rotates through the stator and creates an electric current in the windings of the stator coils 19. This current is emitted by the generator as electrical energy. The rotor 14 has an axis that extends generally longitudinally 20 and a generally solid rotor core 22. The solid core 22 has a high magnetic permeability, and is usually made of a ferromagnetic material, such as iron. In a low energy density superconducting machine, the iron core of the rotor is used to reduce the magnetomotive force (MMF). The reduced MMF minimizes the amount of superconducting coil wire (SC) needed for the coil winding. For example, the iron rotor core can be magnetically saturated at an air-space magnetic field strength of about 2 Tesla. The rotor 14 supports at least one high temperature superconducting winding (HTS) coil winding, which extends longitudinally 34. The HTS coil winding can alternatively be in a seat shape or have some other form that is suitable for a particular HTS rotor design. A coil support system for a track SC coil winding is described. The coil support system may be adapted for different coil configurations to a track coil mounted on a solid rotor core. The rotor includes a pair of end axes that support the core 22. A collector end shaft has slip rings 78 to provide an external electrical coupling for the coil SC. The manifold end shaft also includes a cryogen transfer coupling 26 to a source of cryogenic refrigerant fluid used to cool the SC coil windings in the rotor. The cryogen transfer coupling 26 includes a stationary segment coupled to a source of cryogen refrigerant fluid and a rotating segment that provides the refrigerant fluid to the HTS coil. The opposite end shaft is a drive shaft 30 which may be connected to an energy turbine. The end axes are supported by bearings 25 which provide supports for the entire rotor. Figure 2 shows an illustrative 34. HTS track field coil winding. The SC field winding coils of the rotor include a high temperature superconducting coil (SC) 36. Each coil SC includes a high temperature superconductor, such as wiring conductors BSCCO (BixSrxCaxCuxOx) laminated in a winding compound impregnated with solid epoxy. For example, a series of BSCCO 2223 cabling can be laminated, united and rolled in a coil impregnated with solid epoxy. The SC wire is fragile and easy to be damaged. The SC coil is typically a SC band rolled into layers that is impregnated with epoxy. The SC tape is wrapped in a precision coil shape to obtain narrow dimensional tolerances. The tape is wound around a propeller to form track coil SC 36. The dimensions of the track coil depend on the dimensions of the rotor core. Generally, each track SC coil encloses the magnetic poles of the rotor core, and is parallel to the rotor axis. The coil windings are continuous around the track. The SC coils form a path of resistance-free electrical current around the rotor core and enter the magnetic poles of the core. The coil has electrical contacts 79 which electrically connect the coil to the slip rings 78. The fluid passages 38 for cryogenic cooling fluid are included in the winding of coil 34. Those passages may extend around an outer edge of the coil SC 36 The passages provide cryogenic cooling fluid to the coil and remove heat from the coil. The coolant fluid maintains the low temperatures, for example 27 ° K, in the SC coil winding necessary to promote the superconducting conditions, including the absence of electrical resistance in the coil. The cooling passages have an inlet fluid port 39 and an outlet fluid port 41 at one end of the rotor core. These fluid ports (gas) connect the cooling passages 38 in the coil SC to the tubes on the end shaft of the rotor 24 which extend towards the cryogen transfer coupling. Each track winding HTS 34 has a pair of generally straight side portions 40 parallel to a rotor shaft 20, and a pair of end portions 54 that are perpendicular to the rotor axis. The lateral portions of the coil are subjected to the highest centrifugal stresses. Consequently, the lateral portions are supported by a coil support system that counteracts the centrifugal forces acting on the coil. Figure 3 shows a partially cut-away view of a rotor core 22 and a coil support system for a super high-conductive coil winding (HTS). The coil support systems include a series of coil support assemblies that extend through the rotor core and between opposite sides of the HTS coil winding. Each coil support assembly comprises a tension bar 42 extending through a conduit 46 of the rotor core, and a split coil housing 44 which is fastened to the bar and the spool winding supports. The coil support system provides a structural framework for retaining the coil winding in the rotor. The main load of the HTS coil winding 34 in an iron core rotor is from the centrifugal acceleration during rotor rotation. The coil support assemblies are aligned with the centrifugal load of the coil in order to provide effective structural support to the coil winding under load. To support the side sections of the coil, each tension bar 42 is attached to the split coil housings 44. The housings hold opposite side sections of the coil. The tension rods 42 extend through a series of conduits 46 in the rotor core. These bars are aligned with the quadrature axis of the rotor core. The divided coil housings 44 support the coil winding 34 against centrifugal forces and tangential torsional forces. Centrifugal forces arise due to rotor rotation. The tangential forces can arise from the acceleration and deceleration of the rotor, and the torsion transmission. Because the long sides 40 of the coil winding are enclosed by the split coil housings 44 and the flat ends 86 of the tension bolts, the sides of the coil winding are fully supported inside the rotor. The conduits 46 are generally cylindrical passages in the rotor core having a straight axis. The diameter of the conduits is substantially constant. However, the ends 88 of the conduits can be expanded to a larger diameter to accommodate an insulating tube 52. The tube aligns bar 42 in the conduit and provides thermal insulation between the rotor core and the rod. At the end of each tension bar, the insulating tube 52 holds the coil support structure to the hot rotor and prevents convection between them. Additionally, there is a lock nut 84 connected to the insulating tube 552, which additionally ensures the connection to the tension bar. Lock nut 84 and tube 52 secure the tension bar and housing divided to the rotor core while minimizing heat transfer from the hot rotor to the housing structure.

The insulating tube 52 is formed of a thermal insulating material. One end of the tube may include an outer ring (not shown) that splices the wall of the wide end 88 of the conduit. The other end of the tube includes an inner ring (not shown) that engages the lock nut 84 retaining the tension bar in the insulating tube. The heat from the rotor would have to be conducted through the length of the insulating tube 52 and the locknut 84 before reaching the tension bar. Therefore, the insulating tube thermally insulates the tension rod from the rotor core. The number of ducts 46 and their location on the rotor core depends on the location of the HTS coils and the number of coil housings required to support the side sections of the coils. The axes of the conduits 46 are generally in a plane defined by the track spool. In addition, the axes of the ducts are perpendicular to the lateral sections of the coil. In addition, the conduits are orthogonal to and intersect the rotor axis, in the embodiment shown herein. The number of ducts and the location of the ducts will depend on the location of the HTS coils and the number of coil housings required to support the side sections of the coils. There are generally two categories of support for the super conductor winding: (i) "hot" supports and (ii) "cold" supports. In a hot support, the support structures are thermally insulated from the cooled SC windings. With the hot coil supports, most of the mechanical loading of a super-conductive coil (SC) is supported by structural members extending between the cold coils and the hot support members. In a cold coil support system, the support system is at or near the cold cryogenic temperature of the SC coils. In cold supports, the majority of the mechanical load of the SC coil is supported by the structural coil support members that are at or near the cryogenic temperature. The illustrative coil support system described herein is a cold support in which the tension rods 42, the bolts 43 and the associated split housings 44 are maintained at or near a cryogenic temperature. Because the coil support members are cold, these members are thermally insulated, for example, by non-contact conduits through the rotor core, from the rotor core and the other "hot" components of the rotor. The HTS coil winding and the structural coil support components are all at cryogenic temperature. In contrast, the rotor core is at an "ambient" hot temperature. The coil supports are potential sources of thermal conduction that would allow the heat to reach the HTS coils from the rotor core. The rotor core is heated during the operation. Since coil windings will be fastened in super-cooled conditions, the heat conduction inside the coils from the core should be avoided. The coil support system is thermally insulated from the rotor core. For example, tension bars and bolts are not in direct contact with the rotor. This lack of contact prevents heat conduction from the rotor to the tension bars and coils. Furthermore, the mass of the structure of the coil support system has been reduced to a minimum to reduce thermal conduction through the support assemblies in the coil windings of the rotor core. Each tension bar 42 is an axis with continuity along the longitudinal direction of the bar and in the plane of the track coil. The tension bar is typically made of non-magnetic high-strength alloys such as aluminum or an Inconel alloy. The longitudinal continuity of the tension bars provides the lateral stiffness to the coils that provides dynamic benefits of the rotor. further, the lateral stiffness of the tension rods 42 makes it possible to integrate the coil support with the coils so that the coil can be assembled with the coil support in the rotor core before the final rotor assembly. The flat surface head 86 of the tension bar supports an inner surface of one side of the coil winding. The end 86 of the tension bar may be serrated so that it may be engaged within annular edges 134 of an assembly of two coil housing side panels 124 (see Figure 5). The other three surfaces on the side 40 of the coil winding are supported by the divided housing 44. Each divided housing is assembled around the coil and forms a coil frame in cooperation with the bolt head. This frame supports the coil winding with respect to tangential and centrifugal loads. The frame also allows the coil winding to expand and contract longitudinally. Figures 4 and 5 (and Figure 3) show one half of the illustrative "C" shaped side panels 124 of the divided housing 44. A pair of side panels support the opposite sides of a coil 34. In addition, the side panels they are positioned end to end along each side of a coil to form a continuous coil support assembly along a side section 40 of a coil winding 34. An inner surface of each side panel has a narrow groove 130 to receive the wedge and channel "L" 132 to receive one side of the coil. A side surface and an inner surface of the coil rest on orthogonal surfaces of the channel 132 of the side panel. An opposite side panel is assembled around the coil and supports the same inner coil surface and an opposite coil side surface. The outer surface of the coil is supported by a wedge 126 extending between the side panels on opposite sides of the coil. An individual wedge can be divided (as shown in Figures 4 and 5) and extend half the distance through the coil where it splices with another split wedge. The wedge 126 fits within the narrow slot 130 of a side panel. The wedge includes a channel 127 for receiving the cooling passage 38 on the outer surface of the coil. In addition, the wedge may include a series of holes 131 that are aligned with holes 133 in the upper edge of the side panel. Each pair of these holes 131, 133 receive pins 136 (FIG. 3) that extend through opposite side panels and wedges to hold the upper edges of the side panels and the wedges together. The wedge may be integral to the side panel and extend half the width of the coil, as shown in Figure 4. Alternatively, the wedge may be a separate component that is assembled with the side panel and may extend half or all the distance across the width of the coil to an opposite side panel. In addition, the wedge 126 need not be coextensive with the side panel. The wedge may extend beyond the length of a side panel and engage a slot 130 in an adjacent side panel (as shown in Figure 4). Alternatively, the wedge may be coextensive with the side panel, as shown in FIG. 5. The side panels 124 have a lower flange 135 on which the inner surface of the spool rests. The bolt holes 142 in the lower flange allow the holding bolts to hold the lower portion of the housing 44 together. The lower flange also engages the tension bar 42 or the tension bolt 43 (depending on whether a tension bar is used). solid or a tension rod and a bolt assembly is being used). Each side panel (half shown in Figures 4 and 5) has a middle section 134 of a hole for coupling a tension bar or tension bolt. The side panels shown in Figs. 4 and 5 have a medial section 134 that forms a hole (when assembled with two pairs of side panels) to engage a serrated end of the tension bar 42 (Fig. 5) or the head of a tension bolt 43 (figure 4). The hole formed by the side panel shown in Figure 4 has a uniform hole and an annular flange 137 for coupling the bolt head 43. Alternatively, the hole formed by the middle section 134 of the side panel shown in Figure 5 is sawed and engages the serrated end of a tension bar. Accordingly, the divided housing 44 can be used with a tension rod and bolt assembly, or with a tension rod without a bolt. In addition, a lock nut 138 (see FIG. 6) can be inserted into the threaded hole 134 and the jam nut can have an inner bore and flange for securely retaining a tension bolt head 43. Regardless of the manner in which the bolt Tension or the tension bar is fastened to the lower flange 135 of the side panel, the end of the bolt or bar is secured to splice the inner surface of the coil. In this way the end of the tension rod or bolt directly supports the coil.

The divided housing can be made of a high strength, lightweight material, which is ductile at cryogenic temperatures. The typical materials for the divided housings are aluminum, titanium and Inconel alloys. The shape of the divided housing has been optimized for a low weight. As shown in Figure 6, a series of split coil housings 44 (and associated tension bolts 43. and rods 42) can be positioned along the sides 40 of the coil winding. The tension bolts 43 are screwed into threaded holes (not shown) at the end of the tension bar. The depth to which the bolt screws inside the bar is adjustable. The total length of the tension bar and bolt assembly (whose assembly extends between the sides of the coil) can be changed by turning one or both bolts in or out of the holes in the tension bars. The head of the bolt or the end of the tension rod includes a flange with a flat external surface 86. The flange engages the ring of the divided housing shown in Figure 4. The flat head 86 of the bolt or bar splices an inner surface of the winding of coil 34. The housings are positioned end-to-end along the length of the side portion 40 of the coil. The divided housings collectively distribute the forces acting on the coil, for example, centrifugal forces, substantially on all side sections 40 of the coil. The divided housings prevent the side sections of coil 40 from flexing and bending excessively due to centrifugal forces. The plurality of divided housings 44 effectively retain the coil in place without affecting the centrifugal forces. Although the divided housings are shown to be in close proximity to each other, the housings need only be as close as necessary to avoid coil degradation caused by high bending and tensile stresses during centrifugal loading, torsion transmission and the conditions of transient failure. The coil supports do not restrict the coils of their longitudinal thermal expansion and shrinkage that occurs during the normal start / stop operation of the gas turbine. In particular, the thermal expansion is directed mainly along the length of the side sections. Therefore, the lateral sections of the coil slide slightly longitudinally with respect to the divided housing and tension bars. The coil support system of the tension rods 42, bolts 43 and divided housings 44 can be assembled with the HTS coil windings 34 as they are mounted on the rotor core 22. The tension rods and the divided housings provide an almost rigid to support the coil winding and retain the long sides of the coil winding in place with respect to the rotor core. The ends of the coil may be supported by split fasteners (not shown) at the axial ends of (but without contacting) the rotor core 22. The rotor core and the end axes may be discrete components that are assembled together. The iron rotor core 22 has a generally cylindrical shape 50 suitable for rotation with the rotor cavity 16 of the stator 12. To receive the coil winding, the rotor core has recessed surfaces 48, such as flat or triangular regions or grooves. . These surfaces 48 are formed on the curved surface 50 of the cylindrical core and extend longitudinally through the rotor core. The coil winding 34 is mounted on the rotor adjacent to the recessed areas 48. The coils generally extend longitudinally along the outer surface of the recessed and alreding area of the ends of the rotor core. The recessed surfaces 48 of the rotor core receive the coil winding. The shape of the recessed area is attached to the reel winding. For example, if the coil winding has a seat shape or some other shape, the recesses in the rotor core would be configured to receive the shape of the winding. The recessed surfaces 48 receive the coil winding so that the outer surface of the coil winding extends substantially to an envelope defined by the rotation of the rotor. The outer curved surfaces 50 of the rotor core when they rotate define a cylindrical shell. This rotational envelope of the rotor has substantially the same diameter as the vacuum rotor cavity 16ver Figure 1) in the stator. The space between the rotor casing and the stator cavity 16 is a relatively small free space, as required for cooling by forced flow ventilation only of the stator, since the rotor does not require cooling by ventilation. It is desirable to minimize the clearance between the rotor and the stator to increase the electromagnetic coupling between the rotor windings of the rotor and the stator windings. In addition, the rotor winding of the rotor is preferably positioned so that it extends towards the envelope formed by the rotor and, therefore, is separated from the stator only by the clearance between the rotor and the stator. The rotor core, the coil windings and the coil support assemblies are preassembled. The pre-assembly of the bobbin and the bobbin holder reduces the production cycle, improves the quality of the bobbin holder and reduces the variations of the bobbin assembly. Before the rotor core is assembled with the rotor end shafts and the other components of the rotor, tension rods 42 are inserted into each of the conduits 46 extending through the rotor core. The insulating tube 52 at each end of the tension bar is positioned at the expanded end 88 at each end of the conduits 46. The tube 52 is locked in place by a retaining locknut 84. The bolts 43, if used, they can be inserted before or after the tension bars are inserted into the rotor core ducts. When tension bolts are used, then a locknut 138 is placed on each bolt and then used to secure the bolt against the split housing. The depth at which the bolts are screwed into the tension rods are selected so that the length from the end of a bolt on the tension rod to the end of the opposite bolt is the distance between the long sides 40 of the coil winding. . When the tension rods and the bolts are assembled in the rotor core 22, the coil windings 34 are ready to be inserted on the core. The coil winding 34 is inserted on the rotor core so that the flat ends 86 of the tension rods 42 or the bolts 43 buttress the inner surface of the side sections 40 of the winding. Once the winding has been inserted over the ends of the rod 42 or the bolt 43, the divided housings 44 are assembled on the winding. To assemble each housing, the side panels are placed against opposite sides of the coil, and the shims are slid into the narrow slots 130 of the side panels. The plug is inserted to hold the wedges and the side panels together. Locknut 138 is used to adjust the side panels against the bolt.

The rotor core may be enclosed in a metallic cylindrical shield 90 (shown by dashed lines) which protects the super-conductive coil winding 34 from parasitic currents and other electric currents surrounding the rotor and provides a vacuum envelope to maintain a vacuum strict around the cryogenic components of the rotor. The cylindrical protector 90 may be formed of a highly conductive material, such as copper or aluminum alloy. The coil winding SC 34 is maintained in a vacuum. The vacuum can be formed by the protector 90 which can include a cylindrical layer of stainless steel which forms a vacuum vessel around the coil and the rotor core. The split coil housings, tension rods and bolts (coil support assembly) can be assembled with the coil winding before the rotor core and coils are assembled with the collar and the other rotor components. Accordingly, the rotor core, the coil winding and the coil support system can be assembled as a unit before the assembly of the other components of the rotor and the synchronous machine. While the invention has been described in relation to what is currently considered the most practical and preferred embodiment, it is understood that the invention is not limited to the described modality, but on the contrary, is intended to cover all modalities within the scope of the invention. spirit of the appended claims.

Claims

CLAIMS 1. In a synchronous machine (10), a rotor comprising: a rotor core (22); a super-conductive coil winding (34) extending around at least a portion of the rotor, the coil winding having a side section (40) adjacent to a side of the rotor core; at least one tension bar (42) extending through a conduit (46) in said rotor core; and a housing (44) attached to the tension bar and connected to the side section of the coil winding, wherein the housing comprises a pair of side panels (124). A rotor according to claim 1, characterized in that the side panels (124) are on opposite surfaces of the side section (40). 3. A rotor according to claim 1, characterized in that the housing (44) and the tension bar (42) are cooled by conduction from the coil winding. A rotor according to claim 1, characterized in that the housing further comprises a wedge (126) joining the side panels and splicing an outer surface of the coil winding. A rotor according to claim 1, characterized in that the tension bar includes a bolt (43) having a flat surface (86) that splices the bobbin, and that has a width commensurate with the lateral section. 6. A rotor according to claim 1, characterized in that the tension bar has a serrated end engaging a serrated hole (134) formed by a plurality of side panels. A rotor according to claim 1, characterized in that an assembly of two side panels forms a hole (134) for coupling one end of a tension rod or tension bolt. 8. A rotor according to claim 1, characterized in that the side panel has a pair of orthogonal surfaces (132) that splice the coil. 9. A rotor according to claim 1, characterized in that the housing (44) is formed of a metallic material selected from the group consisting of aluminum, Inconel alloys and titanium. A rotor according to claim 1, characterized in that the tension bar (42) is formed of a non-magnetic metal alloy. 11. A rotor according to claim 1, characterized in that the tension bar (42) is formed of an Inconel alloy. 12. A method for supporting a super conductor coil winding (34) in the rotor core (22) of a synchronous machine (10) comprising the steps of: a. extending a tension bar (42) through a conduit (46) in the rotor core; b. placing the coil winding around the rotor core so that the tension bar extends between the side sections of the coil winding; c. assembling a pair of side panels (124) of at least one housing (44) around a side section of the coil winding; d. secure the side panels together, and e. join the housing to a first end of the tension bar. A method according to claim 12, further comprising repeating the steps of assembling a pair of side panels (124), securing the side panels together, and attaching the housing to a first end of the tension bar. A method according to claim 12, characterized in that the step of assembling a pair of side panels is performed by assembling a plurality of side panels around a flange head (122) at one end of the tension bar . A method according to claim 12, characterized in that the step of assembling a pair of side panels is performed by assembling a plurality of side panels to form a serrated hole (134) and engaging a serrated end of the bar. tension inside the hole. 16. A method according to claim 12, characterized in that the tension rods (42) are inserted in a series of conduits (46) in the rotor core and secured to the coil winding.